Wire-to-wire connectors are used to connect wires to each other. The connector shown in Patent Document 1 is one of two wire-to-wire connectors (the one on the receiving end). This wire-to-wire connector has a cylindrical outer housing having an insertion opening on one end for inserting the other connector of the two wire-to-wire connectors, an inner housing inserted into the outer housing via an assembly opening on the other end of the outer housing, and a retainer for preventing terminal detachment inserted into the inner housing via a window hole provided in the cylindrical wall portion of the outer housing.
This type of connector is usually shipped without wires connected, and the wire connecting operation is performed by the purchaser. The connector can be used by inserting wires with terminals into a terminal holding hole in the inner housing, and then pushing in the retainer to lock the terminal and prevent detachment. In the case of the connector shown in Patent Document 1, the outer housing has to be slid in after the retainer has been pushed in to retain the retainer.    [Patent Document 1] JP06-124745A